I am adding a 14-50 outlet in the garage. Running NM-B 6/3 Romex to existing breaker box. There is room for a 50AMP 240 breaker. I have 200A single phase service. Sheetrock above box. I can drill a hole in the studs above the breaker box and feed wire into breaker box from attic. Because of the existing sheetrock I don't have access to put on a clamp with a nut on the top of the breaker box (without cutting sheetrock). Can I use a simple bushing? I think I need 3/4" or 1" bushing or clamp. The electrician that helped me gave me a 1" bushing. Is that code? I also see snap-in clamps. That would work if I can find one. Do they make 3/4" snap-in clamps? Does code allow the simple nylon/plastic bushing where the wire enters the breaker box? What are my options?
Update: I used the NM95X as suggested in the replies to my question. Here is how it turned out. The 6/3 enters at the top center. I think I did a correct and pretty job. Critiques?
Best Answer
You'll need a 3/4" snap-in NM clamp that can be installed from the inside of the box
You do need a NM clamp (vs a mere bushing) here, first off; a simple bushing does not provide the clamping of the cable jacket required by NEC 312.5(C) for cabinets or 314.17(B)/(C) for boxes. This NM clamp also needs to be installed from the inside of the cabinet, and that limits your options; in fact, the only product I know of offhand that fits the bill is the 3/4" Arlington NM95X, which maxes out precisely at 6/3.